Plate-shears.



PATENTED JUNE 20, 1905.

C. SWAN.

PLATE SHEARS.

APPLICATION FILED MAR.21,1904.

UNITED STATES Patented June 20, 1905.

PATENT OEEIcE.

PLATE-SHEARS.

SPECIFICATION forming part of Letters Patent No. 792,802, dated June 20, 1905.

Application filed March 21, 1904. Serial No. 199,183.

To all whom it may concern:

Be it known that I, CHARLES SWAN, a citizen of the United States, residing at Corry, in the county of Erie and State of Pennsylvania, have invented new and useful Im provements in Plate-Shears, of which the following is a specification.

This invention relates to plate-shears; and it consists in certain improvements in the construction thereof, as will be hereinafter fully described, and pointed out in the claims.

One of the objects of the invention is to provide a plate-shears in which the leverage on the blades Will increase as the cutting-point between the blades recedes from the pivot. One difficulty with shears heretofore made is that while a great leverage is acquired at the initial part of the cut where the cutting-point is near the pivot on ordinary plate only short cuts can be made, for the reason that the leverage on the handles has not been sufficient to carry the cut to the end of the blade Without an excessive effort.

Another object of the invention is to provide the movable blade with an offset, so that the cut may pass along the blade without undue crimping and also that the operating-handle may be freely operated above the plate.

The invention is illustrated in the accompanying drawings, as follows: Figure 1 shows a side elevation of the shears; Fig. 2, a section on the line 2 2 in Fig. 1.

A marks .the blade, which is usually secured to a bench or other base by means of a bend a. While I term this the fixed blade, it of course may be moved. It is as ordinarily operated the fixed blade; but I do not wish to be understood as limiting my invention to one in which the blade is fixed. A movable blade B is pivoted on the fixed blade by the pivot-pin O, the cutting edges of the blades 6 and (0 operating in the usual manner of shears.

Extending upwardly from the fixed blade is a post A. The bell-crank D is pivoted at (Z on this post. It has the arms dand cl, the arms 0Z being provided with the operatinghandle (Z The arm 63 forms one member of a toggle lever, the other member being formed by the link E. The link E is pivoted on the arm (Z at e and on the blade B at b.

' It will readily be seen that when the handle (Z is turned up the available length of the arm 0? increases, and the leverage on the blade consequently decreases, and, in reverse order, as the handle (Z is lowered the leverage increases in the manner of the ordinary toggle-joint. At the same time it will be noted that the cuttin'g-pointthat is, that portion of the cutting edges to and I) which are actually engaged in cuttingcorrespondingly recedes from the pivot C, so that while the actual leverage on the blade'B increases the cutting force is preferably just uniform.

It is desirable on all forms of such cuttingshears to have the offset F, which in the construction shown is formed by placing the link E to one side of the plate B. This permits the metal as it is cut to pass freely along the blade B and at the same time leaves the handle d? above the plate, so that it can be freely operated. This feature of the invention is applicable in a broad way to mechanism wherein the increasing mechanism increasing the leverage is absent. It is, however, particularly desirable with such a mechanism.

What I claim as new is 1. In a plate-shears, the combination of the fixed blade, the movable blade, a handle for operating the shears from the opposite side of the plate from the movable blade, and connecting mechanism between the handle and the movable blade comprisinga link for communicating the action of the handle to the blade.

2. In a plate-shears, the combination of the fixed blade, the movable blade, a handle for operating the shears from the opposite side of the plate from the movable blade, and a connecting mechanism between the handle and the movable blade arranged in the form of a toggle-lever for communicating the action of the handle to the blade with an increasing leverage as the shears are closed.

3. In a plate-shears, the combination of the fixed blade, the movable blade, a handle for operating the shears from the opposite side of the plate from the movable blade, and a connecting mechanism arranged to engage the shank of the movable blade at one side of the plate and communicating to it the action of the handle at the opposite side of the plate, the plate passing between the handle and the blade.

4. In a plate-shears the combination of the fixed blade; a movable blade pivoted thereto; a lever mechanism for operating the shears, said lever mechanism comprising an offset permitting the passage of the plate past the lever mechanism and the operation of the handle at the opposite side of the plate from the movable blade.

5. In a plate-shears the combination of the fixed blade; a movable blade pivoted thereto and a lever mechanism for operating said blades arranged to increase the leverage delivered at the pivot of the shears, as the shears are closed said lever mechanism comprising an offset for permitting the passage of the plate and the operation of the handle at the opposite side of the plate from that of the movable blade.

6. In a plate-shears, the combination of the blades A and B; the pivot (J; the post A on the blade A; the bell-crank lever D pivoted on said post; and the link E forming a connection between the bell-crank lever and the blade B and also an ofiset between the blade A and the handle for permitting the passage of the plate and the operation of the handle above the plate.

In testimony whereof I have hereunto set my hand in the presence of two subscribing Witnesses.

CHARLES SWAN. Witnesses:

H. C. LORD,

M. O. SIILLIVAN. 

